Conventionally, copy machines, document readers and the like are provided with a document support table upon which an original document is placed so as to allow scanning exposure of the original document by an optical system or reading of the original document by a charge-coupled device (CCD). A panel of transparent glass is typically used for the document support table.
More recently, the use of automatic document feeders (ADF) has become widespread, the ADF feeding the original document to an exposure reference position on the document support table, and moving the original document to a specified location after the exposure has been made. Copy machines and the like are often provided with an ADF device; when an original document is fed to the document support table, the original document comes into contact with a feed belt and friction drag is produced between said original document and the feed belt.
The original document transported by a feed belt rubs against the document support table, so as to induce friction drag therebetween which is greater than that produced between the original document and the feed belt, thereby impeding alignment of the original document with the aforesaid exposure reference position and, depending on the characteristics of the paper, causing inadequate transport of the original document. A well-known method of reducing friction drag between the original document and the document support table is the application of silicon wax, oil or like lubricant to the surface of the document support table.
In the aforesaid conventional document support table, the lubricant must be periodically applied about once every several thousand copies because the applied lubricant adheres to the original document and is gradually removed from the document support table. Further, the period between lubricant applications tends to be shortened when a high performance ADF is used, due to the increased consumption of the lubricant in correlation to the high speed of the ADF, thereby complicating maintenance.